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TiDB 5.1.1 Release Notes
Release Date: July 30, 2021
TiDB version: 5.1.1
Compatibility changes
TiDB
- For TiDB clusters upgrade from v4.0 to v5.1, the default value of
tidb_multi_statement_mode
isOFF
. It is recommended to use the multi-statement feature of your client library instead. See the documentation ontidb_multi_statement_mode
for details. #25751 - Change the default value of the
tidb_stmt_summary_max_stmt_count
variable from200
to3000
#25874 - Require the
SUPER
privilege to access thetable_storage_stats
table #26352 - Require the
SELECT
privilege onmysql.user
to access theinformation_schema.user_privileges
table to show other user's privileges #26311 - Require the
CONFIG
privilege to access theinformation_schema.cluster_hardware
table #26297 - Require the
PROCESS
privilege to access theinformation_schema.cluster_info
table #26297 - Require the
PROCESS
privilege to access theinformation_schema.cluster_load
table #26297 - Require the
PROCESS
privilege to access theinformation_schema.cluster_systeminfo
table #26297 - Require the
PROCESS
privilege to access theinformation_schema.cluster_log
table #26297 - Require the
CONFIG
privilege to access theinformation_schema.cluster_config
table #26150
- For TiDB clusters upgrade from v4.0 to v5.1, the default value of
Feature enhancements
TiDB Dashboard
- Support OIDC SSO. By setting the OIDC-compatible SSO services (such as Okta and Auth0), users can log into TiDB Dashboard without entering the SQL password. #3883
TiFlash
- Support the
HAVING()
function in DAG requests
- Support the
Improvements
TiDB
- Announce the general availability (GA) of the Stale Read feature
- Avoid allocation for
paramMarker
to speed up data insertion #26076 - Support the stable result mode to make the query results more stable #25995
- Support pushing down the built-in function
json_unquote()
to TiKV #26265 - Support retrying MPP queries #26480
- Change the
LOCK
record into thePUT
record for the index keys usingpoint get
orbatch point get
forUPDATE
reads #26225 - Forbid creating views from stale queries #26200
- Thoroughly push down the
COUNT(DISTINCT)
aggregation function in the MPP mode #26194 - Check the availability of TiFlash before launching MPP queries #26192
- Do not allow setting the read timestamp to a future time #25763
- Print log warnings when aggregation functions cannot be pushed down in
EXPLAIN
statements #25737 - Add the
statements_summary_evicted
table to record the evicted count information of a cluster #25587 - Improve the MySQL compatibility of the built-in function
str_to_date
for the format specifiers%b/%M/%r/%T
#25768
TiKV
- Make the prewrite requests as idempotent as possible to reduce the chance of undetermined errors #10586
- Prevent the risk of stack overflow when handling many expired commands #10502
- Avoid excessive commit request retrying by not using the Stale Read request's
start_ts
to updatemax_ts
#10451 - Handle read ready and write ready separately to reduce read latency #10592
- Reduce the impact on data import speed when the I/O rate limiting is enabled #10390
- Improve the load balance between Raft gRPC connections #10495
Tools
TiCDC
TiDB Lightning
- Add a retry mechanism for restoring schemas #1294
Dumpling
Bug fixes
TiDB
- Fix the data loss issue that might occur when changing the column type with
tidb_enable_amend_pessimistic_txn=on
#26203 - Fix the issue that the behavior of the
last_day
function is incompatible in the SQL mode #26001 - Fix the panic issue that might occur when
LIMIT
is on top of window functions #25344 - Fix the issue that committing pessimistic transactions might cause write conflict #25964
- Fix the issue that the result of index join in correlated subqueries is wrong #25799
- Fix a bug that the successfully committed optimistic transactions might report commit errors #10468
- Fix the issue that an incorrect result is returned when using merge join on the
SET
type column #25669 - Fix a bug that the index keys in a pessimistic transaction might be repeatedly committed #26359
- Fix the risk of integer overflow when the optimizer is locating partitions #26227
- Fix the issue that invalid values might be written when casting
DATE
to timestamp #26292 - Fix the issue that the Coprocessor Cache metrics are not displayed on Grafana #26338
- Fix the issue of annoying logs caused by telemetry #25760 #25785
- Fix a bug on the query range of prefix index #26029
- Fix the issue that concurrently truncating the same partition hangs DDL executions #26229
- Fix the issue of duplicate
ENUM
items #25955 - Fix a bug that the CTE iterator is not correctly closed #26112
- Fix the issue that the
LOAD DATA
statement might abnormally import non-utf8 data #25979 - Fix the panic issue that might occur when using the window function on the unsigned integer columns #25956
- Fix the issue that TiDB might panic when resolving async commit locks #25778
- Fix the issue that Stale Read is not fully compatible with the
PREPARE
statements #25800 - Fix the issue that the ODBC-styled constant (for example,
{d '2020-01-01'}
) cannot be used as the expression #25531 - Fix an error that occurs when running TiDB alone #25555
- Fix the data loss issue that might occur when changing the column type with
TiKV
- Fix the issue that the duration calculation might panic on certain platforms #10569
- Fix the issue that Load Base Split mistakenly uses the unencoded keys of
batch_get_command
#10542 - Fix the issue that changing the
resolved-ts.advance-ts-interval
configuration online cannot take effect immediately #10426 - Fix the issue of follower metadata corruption in rare cases with more than 4 replicas #10225
- Fix the panic issue that occurs when building a snapshot twice if encryption is enabled #9786 #10407
- Fix the wrong
tikv_raftstore_hibernated_peer_state
metric #10330 - Fix the wrong arguments type of the
json_unquote()
function in the coprocessor #10176 - Fix a bug that the index keys in a pessimistic transaction might be repeatedly committed #10468
- Fix the issue that the
ReadIndex
request returns stale result right after the leader is transferred #9351
PD
TiFlash
- Fix the potential panic issue that occurs when running table scan tasks
- Fix a bug that TiFlash raises the error about
duplicated region
when handling DAQ requests - Fix the panic issue that occurs when the read load is heavy
- Fix the potential panic issue that occurs when executing the
DateFormat
function - Fix the potential memory leak issue that occurs when executing MPP tasks
- Fix the issue of unexpected results when executing the aggregation functions
COUNT
orCOUNT DISTINCT
- Fix a potential bug that TiFlash cannot restore data when deployed on multiple disks
- Fix the issue that TiDB Dashboard cannot display the disk information of TiFlash correctly
- Fix the potential panic issue that occurs when deconstructing
SharedQueryBlockInputStream
- Fix the potential panic issue that occurs when deconstructing
MPPTask
- Fix the potential issue of data inconsistency after synchronizing data via snapshot
Tools
TiCDC
- Fix the support for the new collation feature #2301
- Fix the issue that an unsynchronized access to a shared map at runtime might cause panic #2300
- Fix the potential DDL loss issue that occurs when the owner crashes while executing the DDL statement #2290
- Fix the issue of trying to resolve locks in TiDB prematurely #2188
- Fix a bug that might cause data loss if a TiCDC node is killed immediately after a table migration #2033
- Fix the handling logic of
changefeed update
on--sort-dir
and--start-ts
#1921
Backup & Restore (BR)
TiDB Lightning
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